This is a proposal for the continuation of a training grant at the University of Texas at Austin focusing on interdisciplinary training in the biological bases of behavior. A small select group of behavioral neuroscientists from the Psychology and Zoology departments of the University have joined together to provide training with special emphasis on integrating physiological, developmental, ecological, and evolutionary determinants of behavior. This broad-based approach combines unique, yet fundamental, training in the physiological and psychological sciences. The training program has three primary features. First, there is training in how to conduct investigations in both field as well as laboratory settings. Naturalistic field studies provide clues to the functional links between ecology, physiology, and behavior. Laboratory studies allow for the greater control that is required for the study of underlying mechanisms. From both come animal model systems that aid in the understanding of mental health disorders in humans. Second, we emphasize that only by using an integrative approach is it possible to discover the relationships between the development, physiology, ecology, and evolution of behavior. In this way, the relations between different levels of biological organization are illuminated. Third, students are encouraged to become proficient with contemporary analytic methods needed to exploit successfully different levels of scientific inquiry. All trainees are required to take three didactic courses (neuroscience, behavioral physiology, and human neuropsychology). Throughout their tenure (4 years for predoctoral trainees and 2 years for postdoctoral trainees), trainees attend weekly seminars in the Psychology and Zoology departments. These seminars include summaries of state-of-the-art knowledge in various areas, laboratory demonstrations of new techniques, and discussions of ethical issues in the conduct of research. Trainees are evaluated for their steady progress in scholarship and research in quarterly meetings of the training faculty. A qualifying and a dissertation examination are required of all predoctoral trainees. All of the research service facilities of the Psychology and Zoology departments (computer specialists and electronics and machine shops) are available to the trainees, as well as the well-equipped laboratories of the training faculty, all of whom are recognized authorities in their fields, as evident by sustained productivity in research, invitations to national and international symposia, continual research funding from federal agencies, and extensive experience in providing research training. All of the laboratories comply with NIH requirements.